Everyone tries to rush up through the syllabus levles and think once they are at the top they have arrived. What they don't realize is that by doing this it is like skimming through a book, you may get the gist but you will never understand the story.

Why in tango does the one going backward have the power? What about the other dances? What does it mean to have the power ? If you do promenade in tango who is going backward?

I think the answer depends on the School of thought. In my experience, the man only indicates how much power he wants (presses the accelerator pedal) and the lady produces it. The man then hangs on for dear life.